#include <bits/stdc++.h>
using namespace std;
#define mm(a) memset(a,0,sizeof(a));

int main () {
    int res = 0;
    for (int i = 1901; i <= 2000; i++) {
        if ((i % 4 == 0 && i % 100 != 0) || i % 400 == 0) {
            res += 366;
        } else {
            res += 365;
        }
    }
    cout << res / 7 << endl;
    return 0;
}